Purpose of Pain

There is actually a “no inner pain” alternative which very few (if any) have undergone:

“obeying His Word by doing His Will” (no inner pain but peace and joy instead to endure the physical pain faced):

“Consider it all joy, my brethren, when you encounter various trials, knowing that the testing of your faith produces endurance.” – apostle James (James 1:2 – 3)

“But rejoice inasmuch as you participate in the sufferings of Christ, so that you may be overjoyed when His glory is revealed.” – apostle Peter (1 Peter 4:13)

“For I consider that the sufferings of this present time are not worthy to be compared with the glory that is to be revealed to us.” – apostle Paul (Romans 8:18)

“In all this you greatly rejoice, though now for a little while you may have had to suffer grief in all kinds of trials.” – apostle Peter (1 Peter 1:6)

“And to him they agreed: and when they had called the apostles, and beaten them, they commanded that they should not speak in the name of Jesus, and let them go.  And they departed from the presence of the council, rejoicing that they were counted worthy to suffer shame for His Name.” – apostle Luke (Acts 5:40 – 41)

“Now I rejoice in my sufferings for your sake, and in my flesh I do my share on behalf of His body, which is the church, in filling up what is lacking in Christ’s afflictions.” – apostle Paul (Colossians 1:24)

Regarding the Lord Himself Who set the example for this (God didn’t just talk but also walked His Talk – A Great Difference):

“fixing our eyes on Jesus, the author and perfecter of faith, who for the joy set before Him endured the cross, despising the shame, and has sat down at the right hand of the throne of God.” – Anonymous author in (Hebrews 12:2)

P/S:

Any failure from doing the above merits a lesson in “inner pain” with varying degrees (which may continue beyond this life to at most, the age to come).